It is the object of identification systems to bring articles of any kind together in place and time transiently to form a systematic whole. To this end as a rule the articles are provided with a code carrier, code readers or rather code announcers being located at predetermined places to-determine on the one hand the article itself (identification) and on the other hand its time and place (location). The systematic whole is obtained by bringing these "announcements" together for data processing by data processing means.
Generally the code is transmitted in a contactless manner, for example, by optical or electromagnetic transmission processes, the main problem being to achieve complete, reliable code transmission, if necessary in the shortest possible time. Positioning errors of the code carrier in front of the code reader lead to deficient reading speeds or altogether faulty performance, so that the positioning and recognition of the correct position of a code carrier in front of a read-write location is one of the basic preconditions for the operation of an identification system.